1. Field of the Invention
The invention concerns an icebreaking ship having a forward quarter designed like a pontoon with the underside of the bow extending from the ship bottom roughly to the beginning of the front third of the bow and rising obliquely forward to above the water line. The lateral edges of the bow in the vicinity of the water line bear icebreaking or cutting means and the width of the icebreaking or cutting means in the vicinity of the water line is greater than the width of the water line of the afterbody of the hull. The hull can also have balcony-like flanks on both sides, with a parapet that is preferably oriented roughly vertically. The balcony undersides adjoining the parapet can be oriented obliquely downward and the balcony support adjoining oblique surfaces, until the transition to the essentially flat ship bottom, can be oriented roughly vertically. The water line of the hull runs roughly parallel, and preferably somewhat outward to the half width of the underside of the balcony.
2. Background Information
Icebreakers of this type, which were disclosed in German Patent 4101034, have recessed waistline-like indentations in the body of the ship on both sides adjoining the pontoon-like forward quarter.
Furthermore, in this known icebreaker, the balcony-like flanks adjoining the indentations extend all the way to the stern.
It is true that, with appropriate dimensions of depth and length, the waistline-like indentations essentially provide a small turning circle radius during turns of the ship and, consequently, good maneuverability. However, such indentations tend to require significant construction interventions in the structure of the ship's hull and, consequently, increased cost.
Moreover, the indentations tend to disrupt the flow of water currents along the ship's side, which circumstance usually has a disadvantageous effect on resistance, particularly during forward travel in ice-free waters.